I've just recently read the last updated chapter of shadow house, and I absolutely loved it.
Solid taste. Be sure to check out the author's other work,
Kuro, if you haven't already.
For other series with particularly unique fantasy worlds, I'd recommend:
Gembutts. It's (strangely) popular enough that you probably might have already come across it, but there's very little like it and its world out there.
The Girl from the Other Side is one of the better currently ongoing "badass/monster and his loli"-type manga right now, and also has an interesting world/plot going on as well.
It's been a long time since I read it, but I remember quite liking
Amagoi's weird Mushroom/rain-themed fantasy world.